The invention relates to a device for fixing interior coverings in motor vehicles.
It is known to an increasing extent to construct motor vehicle doors in modular fashion. In the modules which have become customary up until now, three structural groups have been assembled, namely the door outside panel, the sheet metal support plate and the door interior covering. The door outside panel thereby forms the closure for the bodywork and holds on the door interior covering the sheet metal support plate which serves inter alia to fix the closing devices, speaker systems, window lift drive mechanisms etc. The door interior covering has, as a rule, an arm rest, speaker openings and storage pockets and is fitted as one part closing the inner trim.
Through the separate parts described, during final assembly the three structural groups which have been pre-assembled and supplied as such are brought together in succession, which requires two assembly operations. In order to connect the interior covering to the other structural groups, it is necessary to use different variations of screws and clips. By way of example, it is necessary to undertake screwing from inside the door whereby the screw head is covered with a separate cap to reduce the visual impairment. The drawback here is the additional work required, together with the associated additional costs, and the danger of losing the caps or forgetting to fit them.
Furthermore, there is the possibility of screwing through the door outside panel or through the door base plate. Here there is the danger that the door which has already been painted becomes scratched. Similarly, as a rule, a cover strip has to be provided which places restrictions on the freedom of design.
Since the ability to dismantle the structure is required, fixing by using retainer clips does not guarantee any secure fixing of the interior covering since the clips can only take up restricted axial forces.
From DE 44 38 309 A1 an adapter is known which is integrated secured against rotation in the door interior covering and through which a fastening clip with radially expanding fingers can be pushed through an opening in the bodywork by pressing onto the inside panel of the door. After passing through the opening the fingers spread out and fix the interior covering of the door against the bodywork. The fastening clip can only absorb restricted axial forces since the fingers which project through the opening are radially displaceable.
From DE 195 29 883 A1 a connecting element is known for a vehicle component part where a screw is turned into an expanding dowel shaft so that the expanding dowel shaft widens out and fixes the component part against a corresponding holder. The screw thereby has to be fully screwed into the expanding dowel shaft in order to produce a sufficiently solid connection of the component part which is to be connected with the holder. Similarly for dismantling, the screw has to be completely unscrewed out from the dowel shaft so that high assembly and dismantling costs and times are incurred.
The object of the present invention is therefore to produce a fixing device which ensures a cost-effective simple assembly of an interior covering or a component part fixed on the interior covering. Furthermore a solid fastening which is simple to dismantle is also to be ensured without detracting from the overall visual appearance.
By integrating an adapter into the interior covering, it is not necessary to fit any separate cover parts which could become lost or forgotten. Sealing the screw hole is thus possible without any extra measures. Furthermore, in this way it is easy to fix component parts such as window lifters or sheet metal support plates mounted on the interior covering so that these in turn are in a position to absorb higher forces.
Although there are different ways in which the adapter can act on the fixing means, rotation and displacement is normally the easiest. For this, it is favourable if the adapter is integrated rotationally movable and axially displaceable in the interior covering so as to guarantee a simple and easy operation.
In a further development of the invention, the fixing means are in active connection with the interior covering and form one functional unit. The fixing means is in one variation more advantageously connected directly to the interior covering so that a simple association with the adapter can be produced.
In one design of the invention, the fixing means are fixed on a support plate or window lifter connected to the interior covering so that when fixing the interior covering the fixing means need still only be operated according to its configuration, for example rotated or axially displaced.
In one advantageous design of the invention, the adapter is loaded by a spring element against the assembly direction whereby it is pressed in the direction of the interior covering. The adapter thereby always occupies one position which ensures a smooth closure from the interior covering to the interior. It is economical and expedient to design the spring element as a plastics part integrated into the interior covering.
More particularly, when a solely longitudinally displaceable adapter is mounted on a curved surface, a guide is advantageously provided in a slide guide or in a thread since in this way it is ensured that a smooth surface is formed on the interior covering when the adapter slides back as it is turned or brought back to its starting position. Apart from the visual aspects, a flush closure with the interior covering is also advantageous for reasons of safety since injury through protruding edges can be avoided.
A screw bolt has proved to be a cost-effective proven embodiment of the fixing means. By screwing, it is possible to achieve a fixed yet releasable connection. Similarly, the shape of the screw bolt head can be simply adapted to the relevant requirements. Through screwing it is possible to compensate without problem any possible inaccuracies in the production since a very fine adaption to the relevant conditions can be achieved by adjusting the screw-in length.
Preferably, an abutment is attached to the screw bolt, for example in the form of a shoulder, a collar or a welded-on disc, whereby the screw bolt need only be screwed in up to the abutment in order to fix the interior covering on the inside door panel.
When configuring the adapter, it is advantageous if the maximum displacement path of the adapter is greater than or equal to the screw-in length of the screw bolt so that it can be guaranteed that screwing in can be completed to the full extent and faulty fastening of the interior covering through premature loosening of the connection between adapter and screw bolt cannot occur.
In one variation of the invention, the interior covering is fixed on a bodywork part through at least one expanding snap-hook which has an integral locking bolt. The snap-hook thus forms a type of casing whose outer diameter corresponds in one assembly position to the opening in the door outside panel through which the snap-hook is passed for the purpose of fixing. By knocking in or turning the locking bolt into a locking position, the snap-hook widens out and thus fixes the interior covering secure.
Through the snap-hook, it is possible to achieve a secure fastening with which axial forces can also be taken up. The integral shaping reduces the number of parts and guarantees the correct alignment and positioning of the locking bolt.
Furthermore, a simple assembly and dismantling is possible without great effort and the snap hooks cannot break as opposed to the clips previously used.
Advantageously, the locking bolt is connected by its lower end to the interior covering through an ideal break point in the region of the insert opening so that through a once only application of force the locking bolt can be inserted into the snap hook and fixes the interior covering. It is thereby expedient if the lower end of the locking bolt is formed paddle-shaped; thus, the width B is greater than the thickness D of the paddle. On the one hand a large expanding action can be achieved and on the other by turning the locking bolt the expansion can be cancelled and the snap hook can be brought into the initial assembly position.
In order to ensure a secure retention of the position occupied by the locking bolt, a detent catch can be provided in the lower end of the hollow cavity in a locking or dismantling position of the locking bolt which makes assembly easier. For control purposes, it is advantageous if the locking bolt has markings for indicating the locking position.
For reasons of visual improvement and a smooth surface closure, the locking bolt has a countersunk head with a worked profile at its end facing the interior covering.
In order to facilitate or enable the expansion, the snap hook can be preferably slit at least in part.